Quick question about Kynoch .303 7Z ball

[Edward Horton]

spinecracker

Have you ever thought about reloading for the .303 instead of shooting old surplus corrosive ammunition.

Or do you enjoy putting on a pot of tea and poring boiling water down the bore.

[spinecracker]

If it involves putting a kettle on so I can have a cuppa, then I'm happy

To be serious, I am selling off surplus .303 to help pay for restorations and, eventually, reloading gear. I've even put a listing on here and at the gunboards forum. I did enjoy shooting 1944 DAC .303 rounds through my 1944 Long Branch, though For old corrosive ammo, I was still getting 2 MOA at 100 yards with open sights (I REALLY need new glasses), which was as good as I could shoot with that rifle anyway lol.

[farmritch]

I might be interested in some of that ammo
I'm in Northern Indiana

Farmritch

[Baya727111]

Are you aware that the z means that this ammo is designed for machine gun use and not smle use. It is loaded about 300Fps hotter and was at one time banned by brittish for use in smle due to the damage it can do to barrels - i wouldnt use it in my favourite gun

[spinecracker]

Are you aware that the z means that this ammo is designed for machine gun use and not smle use. It is loaded about 300Fps hotter and was at one time banned by brittish for use in smle due to the damage it can do to barrels - i wouldnt use it in my favourite gun

Baya, could you please state the sorce of your information, as I was under the impression that the "z" suffix only indicates that the round is filled with nitrocellulose, not cordite. If Mk.VIIz is only for machine gun use, then I would have to find a reason as to why I have seen it on stripper clips in the original boxes.

[Amatikulu]

The "z" is a british/commonwealth designation for the use of nitro-cellulose powder. See following link:

http://www.dave-cushman.net/shot/303headstamps.html

[Baya727111]

Skennerton (The lee enfield story) makes specific reference to the mk7z being for machine gun use on about page 68. Ill confirm the page number when i get home tonight

[Baya727111]

page 222 (Skennerton, The lee enfield story) has reference to mk7z ball being high velocity machine gun ammunition. The passage goes on to say that tests showed that barrels wore twice as fast with z ammo than with standard mk7 ball - 12000 rounds to 6000 rounds

[spinecracker]

Does anyone have ballistic data on the Mk7z ammo? I am wondering how much the extra 300fps mentioned by Baya changes the point of impact. I just rebedded my No.4 Mk.1 (cork and paper shims only in the right places, as discussed on this forum in the past), and the rounds were striking about 6 1/2 inches high of point of aim at 100 yards (using micrometer sight set to 200 yards - I know the rounds, in a perfect world, should strike about 3 inches high at 100 yards using military .303 MK.7 rounds). On the plus side, the grouping shrank from 3 inches to 1 3/8 inches, and I think that I can shrink that down further after I get new glasses (things are getting pretty blurry beyond 75 yards now - yikes!). I will be trying the rifle out with Prvi .303 in the very near future to see what kind of difference this will make, and will then replace my front sight for the correct height as necessary.

[Mk VII]

7z is not MG ammunition, nor is it high velocity, unless the printed passage contains a typo and was referring to 8z.
If you use NC and cordite loads in the same barrel you will get accelerated wear.